1. Field of the Invention
The present invention relates to a method and apparatus for manufacturing an electric motor of the type wherein a cylindrical stator core circumferentially dividable to plural core components is shrinkage-fit in a circular internal surface of a motor housing.
2. Discussion of the Related Art
In electric motors of the type that a stator core is dividable into a plurality of core components, a stator core is constituted, taking the work-to-easy capability in winding process into consideration, by effecting a winding process on each of the core components and then by integrating the core components. Then, a shrinkage fitting process is carried out. Specifically, the stator core is inserted into a thermally expanded cylindrical housing, whereby the stator core is securely tightened circumferentially within the cylindrical housing which then shrinks thermally to a smaller diameter.
However, in the prior art motor manufacturing method, the respective core components are displaced with respect to each another in the course of the cylindrical housing shrinking thermally. This causes air gaps between the stator core and a rotor around the same to be uneven, so that an unfavorable influence is exerted on the torque performance or the like of the electric motor so manufactured.